diff options
| author | Stratos Karafotis <stratosk@semaphore.gr> | 2014-07-18 17:37:25 +0200 |
|---|---|---|
| committer | Rafael J. Wysocki <rafael.j.wysocki@intel.com> | 2014-07-21 13:43:18 +0200 |
| commit | ac658131d79e775efb0b819cc5a833e581d4de28 (patch) | |
| tree | 83efd36c570136f8a3989bc70970fb88b46a543d /drivers/cpufreq | |
| parent | cpufreq: intel_pstate: Disable interrupts during MSRs reading (diff) | |
| download | linux-ac658131d79e775efb0b819cc5a833e581d4de28.tar.xz linux-ac658131d79e775efb0b819cc5a833e581d4de28.zip | |
cpufreq: intel_pstate: Keep values in aperf/mperf in full precision
Currently we shift right aperf and mperf variables by FRAC_BITS
to prevent overflow when we convert them to fix point numbers
(shift left by FRAC_BITS).
But this is not necessary, because we actually use delta aperf and mperf
which are much less than APERF and MPERF values.
So, use the unmodified APERF and MPERF values in calculation.
This also adds 8 bits in precision, although the gain is insignificant.
Signed-off-by: Stratos Karafotis <stratosk@semaphore.gr>
Signed-off-by: Dirk Brandewie <dirk.j.brandewie@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Diffstat (limited to 'drivers/cpufreq')
| -rw-r--r-- | drivers/cpufreq/intel_pstate.c | 3 |
1 files changed, 0 insertions, 3 deletions
diff --git a/drivers/cpufreq/intel_pstate.c b/drivers/cpufreq/intel_pstate.c index ff3c5624972c..129ffb2853dc 100644 --- a/drivers/cpufreq/intel_pstate.c +++ b/drivers/cpufreq/intel_pstate.c @@ -584,9 +584,6 @@ static inline void intel_pstate_sample(struct cpudata *cpu) rdmsrl(MSR_IA32_MPERF, mperf); local_irq_restore(flags); - aperf = aperf >> FRAC_BITS; - mperf = mperf >> FRAC_BITS; - cpu->last_sample_time = cpu->sample.time; cpu->sample.time = ktime_get(); cpu->sample.aperf = aperf; |